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Thursday, August 14, 2014

Weekly Hydro-meteorological Report, 14 Aug, 2014


Monitoring and Prediction

Rather heavy rainfall events were observed in south western and north eastern coastal region of the country during the past week. Despite these events severe drought condition still persists in north central region of the country. Higher rainfall is expected in the next week by some climate models while the presence of the MJO in the Indian Ocean shall enhance rainfall in Sri Lanka.
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Weekly Monitoring:: Light rainfall was observed in south western and eastern regions of the country on the 5th of August. On the 6th no rainfall was observed in any part of the country. Thereafter heavy rainfall up to (100 mm) was observed in North eastern coastal regions and south western region on the 7th and 8th. Rainfall diminished on the 9th of August and on the next day once again high rainfall was observed in north eastern coastal area and the adjacent sea. Colombo and Badulla districts received rainfall up to 20 mm on the 11th.

Monthly Monitoring:A less than average rainfall was observed throughout the country during July.


14-day prediction:Up to 55 mm rainfall is expected in the entire country during 13th- 19th of August and during 20th -26th rainfall shall decrease with only up to 25 mm rainfall expected in south western Sri Lanka.

IMD WRF Model Forecast & IRI forecast: According to the IMD WRF model heavy rainfall (65 mm) is expected in the south western region of the country during 15th and 16th of August. Apart from this eastern region of the country shall receive rainfall too. Based on IRI prediction south western region of the country shall receive total precipitation up to 200 mm during 13th- 18th of August. Up to 150 mm of rainfall is expected in north eastern coastal region and up to 50 mm rainfall in the north and north central region during this period. Unusually heavy rainfall events are not expected in any part of the country during these six days.

Seasonal Prediction:As per IRI Multi Model Probability Forecast issued on July 2014; for August 2014 to October 2014, the precipitation shall be climatological while there is a 70% chance that temperature shall be above normal.

PACIFIC SEAS STATE August 7, 2014 :During June through July the observed ENSO conditions remained near the borderline of a weak El Niño condition in the ocean, but the atmosphere so far has shown little involvement. Most of the ENSO prediction models indicate more warming coming in the months ahead, leading to sustained El Niño conditions by the middle or late portion of northern summer.
INDIAN OCEAN STATE :A 0.5⁰C positive sea surface anomaly was observed around Sri Lanka.
MJO STATE :MJO is at phase 2 in the Indian Ocean and shall affect rainfall in Sri Lanka.